Table 5.

In vitro fermentation of a finishing diet using donor rumen fluid inoculum from treatment and temperature adapted steers

Items1	TRT2		TEMP3		SEM	P value
	CON	ADY	TN	HS		TRT	TEMP	TRT × TEMP
Inoculum pH	6.23	6.28	6.59a	5.91b	0.087	0.6991	0.0116	0.6473
Final pH	6.23	6.12	6.20	6.15	0.063	0.0986	0.3910	0.6681
Total gas, mL	25.1	27.1	24.5	27.6	4.57	0.4420	0.2580	0.6946
Rate of fermentation, h−1	11.9	16.7	15.8	12.8	2.31	0.2320	0.4189	0.5541
Lag time, h	0.524	0.520	0.586	0.458	0.195	0.9806	0.4607	0.2629
NDFd, %	36.4	46.4	45.5	37.3	12.0	0.5448	0.6165	0.3988
TDN,%
kp 2%/h	80.8	80.9	80.4	81.3	0.436	0.7869	0.1743	0.7244
kp 4%/h	79.2	79.3	79.2	79.3	0.323	0.8726	0.7655	0.1692
kp 6%/h	78.2	78.2	78.1	78.3	0.466	0.8752	0.8189	0.1651
ME, Mcal/kg
kp 2%/h	2.92	2.92	2.91	2.94	0.019	0.7944	0.1861	0.7944
kp 4%/h	2.86	2.87	2.86	2.87	0.017	0.9093	0.7177	0.1411
kp 6%/h	2.83	2.83	2.83	2.83	0.017	0.9052	0.9052	0.1474
CH4, g/L gas	0.143	0.069	0.110	0.102	0.033	0.2106	0.8712	0.8866
CH4, g/kg DM	18.8	8.70	13.7	13.8	5.28	0.2684	0.9855	0.9445

^a,bLeast squares means within a row with different superscripts differ at P < 0.05.

¹Items are variables that represent the rumen fluid inoculum or its fermentation effects of a finishing diet. Inoculum is initial pH from the donor steer. Final pH is after 48 h of fermentation in vitro. Total gas production from fermentation of 0.2 g of the finishing diet. NDFd = NDF digestibility. ME is shown with passage rates (kp) of 2, 4, and 6%/h.

²Treatment is control fed (CON) or control + 3 g/d of an active dried yeast (ADY).

³Temperature is thermoneutral [TN; 18 ± 0.55 °C; 20% relative humidity (RH)] or heat stressed (HS; 35 ± 0.55 °C; 42% RH).